1. Field of the Invention
The present invention relates to an illumination system and an illumination method that illuminate an illuminated object.
2. Description of the Related Art
For example, Jpn. Pat. Appln. KOKAI Publication No. 2008-26698 discloses a luminescent device as a light source device having a configuration capable of detecting a broken wire with high accuracy. The light source device includes a light source, a lens, a connector, a light guiding member, and an optical component. The light source includes a semiconductor light-emitting device that emits light, for example, excitation light. The lens condenses light emitted from the semiconductor light-emitting device. The connector is a component where light is condensed by the lens. The light guiding member is connected to the connector. The optical component is arranged at a distal end of the light guiding member. The light guiding member also guides light condensed from the connector. The light guiding member has, for example, an optical fiber. Light is guided into the optical component by the light guiding member.
The light source device also includes an optical branching member disposed between the lens and connector to branch light (reflected light, return light) returning from the optical component and a photoreceptor that receives light branched by the optical branching member. The photoreceptor functions as a detector that detects abnormalities of the light source device, for example, a broken wire of a light guiding member by detecting light.
In Jpn. Pat. Appln. KOKAI Publication No. 2008-26698 described above, the optical branching member is arranged between the lens and connector and so blocks excitation light from the light source toward the optical component. Accordingly, losses of excitation light from the light source toward the optical component increase, leading to lower emission efficiency of the light source device.
In addition, detection items that can be detected by reflected light are limited, which decreases detection accuracy. To improve detection accuracy, it is necessary to increase the number of detection items. To increase the number of detection items, a plurality of detecting portion is needed. If the plurality of detecting portions is disposed, the light source device increases in size.